n = int(input())
blocks = []
for _ in range(n):
    w, s = map(int, input().split())
    blocks.append((s + w, w, s))

# Sort blocks by the sum of s_i and w_i in ascending order
blocks.sort()

# Initialize DP array where dp[k] is the minimal cumulative weight for k blocks
dp = [float('inf')] * (n + 1)
dp[0] = 0

for sw, w, s in blocks:
    # Update in reverse to prevent using the same block multiple times
    for k in range(n, 0, -1):
        if dp[k-1] <= s:
            # Check if adding this block to k-1 blocks is better
            dp[k] = min(dp[k], dp[k-1] + w)

# Find the maximum number of blocks that can be stacked
max_blocks = 0
for k in range(n, 0, -1):
    if dp[k] < float('inf'):
        max_blocks = k
        break

print(max_blocks)